In the drilling or reworking of oil wells a great variety of downhole tools are used. Many downhole tools for use in oil and gas wellbores have drillable components made from metallic or non-metallic materials. One common downhole tool is used to seal tubing or other pipe from the casing of the well such as when it is desired to pump a fluid slurry down the tubing and to force the fluid down into a formation. It is necessary in such cases to seal the tubing with respect to the well casing and to prevent the fluid pressure from lifting the tubing out of the well. Downhole tools referred to as packers and bridge plugs are designed for these general purposes and are well known in the art of producing oil and gas. Bridge plugs generally completely isolate the portion of the well below the bridge plug from the portion thereabove. Such bridge plugs may often be made of drillable components so that they can be drilled from the well after use.
A frac plug is another commonly used well tool. Frac plugs are typically set in a well to isolate the portion thereabove from the portion therebelow so that fluid can be forced into a formation above the frac plug. When frac plugs are set in the well, however, they will allow flow in one direction. Frac plugs therefore may generally be used when it is desired to produce fluid from zones above and below the frac plug. When fluid is pumped into a well above a frac plug so that pressure above the frac plug is greater than the pressure therebelow, the frac plug will prevent flow downwardly therethrough so that the fluid may be forced into a formation thereabove. Once such treatment is completed and pressure below the frac plug is greater than the pressure thereabove, fluid from below the frac plug may flow upwardly through the frac plug and along with fluid from any formations above the frac plug can be flowed to the surface. While both frac plugs and bridge plugs are known, there are no known tools that are easily convertible from frac plugs to bridge plugs.